So, how many servers are actually involved here? You said you'd already installed the Master, which comes with its own client binaries (as I mentioend). So that server is happy.
Are you saying you've got a second piece of hardware that you want to back up, and so need to install the client binaries on ? If so, possible options :
1) Push the install from the Master.
a) Add the client name to a policy. It doesn't matter what policy, could be entirely empty, it just has to be listed in one. Make sure the hardware/OS is correct though.
b) Look at /usr/openv/netbackup/bin/install_client_files for the installation options needed. Your command will probably end up being something like "/usr/openv/netbackup/bin/install_client_files sftp myserver.domain.net root"
2) Install the client binaries via CD or giant installer (NetBackup_6.5_CLIENTS1, 2, or 3) directly onto the client server. Then apply patches to bring it up to date with whatever version is on your Master (6.5.4 I believe you said).
I absolutely recommend option #1 as the easiest. =)